An active range-gated Millimeter-Wave (MMW) imaging system can yield high resolution three-dimensional images of objects obscured from visual view by smoke, fog, forestry or even non-metallic walls of dwellings and the like. Such a device has many applications in military and homeland defense environments.
The transmit portion of such a system must illuminate each pixel of the scene with high-power to see through the obscurations. Narrow beam widths and short (≦100 picoseconds) pulses are required, respectively, for the high angular and range resolution necessary for imaging. Solid state (i.e., transistor-based) power generation is advisable for small size and high reliability. Narrow beam widths are compatible with small size at MMW frequencies. Unfortunately, currently-available MMW transistors are low power devices (both in terms of average and peak power) that work best when operated in long pulse or continuous wave (CW) modes. Thus, there remains a need for an imaging system that takes advantage of solid state power generation available from MMW transistors while still producing the narrow beam widths and short pulses required for high resolution imaging.